Recently, in the medical field, when performing various medical procedures (for example, examinations and surgeries), it is conceivable to attach various types of medical tools to the front edge of an arm unit, and by controlling the driving of the such a robot arm apparatus, observe a surgical site of a patient or perform various treatments on the surgical site of the patient. With such a robot arm apparatus, various medical procedures are performed by causing the medical tool attached to the front edge of the arm unit to touch the patient, or by inserting the medical tool into a body cavity of the patient. For this reason, driving control of the robot arm apparatus that takes safety into consideration is demanded so that the patient is not injured by the medical tool.
For example, Patent Literature 1 discloses technology for a robot apparatus in which an insertion guide trocar is inserted into a patient's body, a manipulator having a treatment tool is attached to the front edge is passed through the cannula of the trocar and inserted into the patient's body cavity, and various treatments are performed. The technology provides a pressure sensor on the outer circumferential wall of the trocar, and switches between a free state allowing the manipulator to move freely and a locked state that locks the manipulator in place, depending on a detection value from the pressure sensor.